http://www.huawei.com/enterprise/dbs3900.do
DBS3900 Product Description: The DBS3900 WiMAX is the distributed WiMAX BS developed by Huawei and complies with IEEE 802.16e standards. Currently, the DBS3900 WiMAX satisfies the application requirements of high-end mobile WiMAX networks, and thus is applicable to global markets. Its coverage and capacity are expanded through 4T4R multi-antenna technologies, its maintainability and testability are improved, and thus it provides subscribers with the wireless broadband access services of large capacity and high quality. Product Appearance The DBS3900 WiMAX uses the modular design. It has only two basic functional modules: BBU and RRU. The BBU communicates with the RRU through the high-rate CPRI interface. The RRU3702 is connected to the BBU3900 through optical fibers and to the antenna system through feeders or jumpers
Benefits: The DBS3900 WiMAX adopts advanced technologies, has high performance, and reduces the network construction cost. Environment Protection The RRU3702 uses highly-efficient power amplification technologies to reduce power consumption, thus facilitating energy saving and emission reduction. The RRU3702 works in natural cooling mode without any cooler, thus reducing power consumption. With software configuration, an RRU3702 can be used as one 4T4R RRU or split into two 2T2R RRUs. When the RRU3702 is configured as two 2T2R RRUs, it can cover two sectors. In this way, the number of required RRU3702s and the power consumption of the BS decrease. The RRU3702 supports three carriers. When the number of subscribers increases, multiple carriers can be configured on one channel to expand capacity. In this way, no RRU needs to be added, and the operator's investment is reduced. High-Performance Network Coverage With advanced technologies, the DBS3900 WiMAX implements wide coverage and has high network performance. It supports multi-antenna technologies, with which multiple types of gain (such as power gain, space diversity gain, space multiplexing gain, array gain, and interference suppression gain) can be obtained so that coverage is expanded and system capacity is improved. − On the downlink, the following multi-antenna technologies are adopted: MIMO A, MIMO B, CDD, and BF (that is supported only when the BS uses the 4T4R technology). The BF technology is a method of weighting target subscriber channels to form narrow beams directed to the subscribers. With this technology, array gain and diversity gain can be obtained to expand coverage. In addition, a narrow beam is formed for each subscriber so that the energy of each narrow beam is intensive. Therefore, the interference on the subscribers in neighbor cells is reduced. − On the uplink, the following multi-antenna technologies are adopted: CSM, MRC, IRC, and MIMO (that requires the two-antenna transmission mode supported by the MS). The MIMO technology improves throughput and coverage on the uplink. It supports HARQ, which integrates FEC and ARQ to improve transmission quality and expand coverage. It supports open loop and closed loop power control to minimize fading effects and interference, thus improving transmission quality. It supports AMC, and thus the system specifies appropriate modulation and coding modes according to channel quality. − When channel quality is good, the high-order modulation scheme and high-rate coding mode are used to achieve higher transmission rate.
− When channel quality is poor, low-order modulation scheme and low-rate coding mode are used to ensure transmission link quality. It supports the 64QAM technology. A high-order MCS is used on the uplink, and thus each subscriber occupies a relatively few time frequency resources. In this way, the system can serve more subscribers, and throughput and capacity are improved on the uplink. Easy Installation for Less Cost The DBS3900 WiMAX is compact and light, and supports multiple installation modes to reduce the footprint and the labor cost. The RRU is small and light [21 kg (46.31 lb)], and thus it can be installed on a pole, tower, wall, or stand. The RRU can be installed near the antenna system to reduce feeder length and loss so that the feeder cost is reduced. The BBU can be installed in a 19-inch cabinet (such as a GSM cabinet or an APM30H) to avoid extra cost, as shown in Figure 1-2.
WiMAX Network with High Security The DBS3900 WiMAX supports device authentication, subscriber authentication, message authentication, and air interface data encryption to improve network security. Device authentication and subscriber authentication can effectively prevent unauthorized devices and subscribers from accessing resources and service on the WiMAX network. Message authentication is implemented through the CMAC to ensure the validity of management messages and to prevent the messages from modification and forgery. Air interface data encryption ensures the security of the data transmitted over the air interface and prevents subscriber data from interception and modification. Reliable Clock Synchronization As a synchronous communications system, the WiMAX system requires accurate synchronization signals. The DBS3900 WiMAX obtains satellite synchronization signals in three ways: A GPS satellite card is integrated into the main control board and connects the satellite antenna and the device, and thus GPS satellite signals can be received. When both GPS satellite signals and GLONASS satellite signals need to be received, the USCU must be installed. The GPS/GLONASS satellite card is integrated into the USCU and connects the satellite
antenna and the device, and thus GPS satellite signals and GLONASS satellite signals can be received. Then, the satellite card calculates and combines two types of signals to obtain more accurate signals. The IEEE1588V2 clock synchronization technology is supported. After obtaining and processing GPS clock signals, the IEEE1588V2 server provides clock signals for the BSs on the network through IP packets.
